Press for dewatering of fibrous materials



.July 7, 1970 J. c. F. c. RICHTER PRESS FOR DEWATERING OF FIBROUS MATERIALS Original Filed July 10, 1967 United States Patent 3,518,935 PRESS FOR DEWATERING 0F FIBROUS MATERIALS Johan C. F. C. Richter, St. Jean Cap Ferrat, France, assignor to Aktiebolaget Kamyr, Karlstad, Sweden, 21 company of Sweden Continuation of application Ser. No. 652,265, July 10, 1967. This application May 19, 1969, Ser. No. 851,510 Claims priority, application Sweden, July 15, 1966, 9,677/66 Int. Cl. B30b 9/06 US. Cl. 100-116 9 Claims ABSTRACT OF THE DISCLOSURE A press for pressing water out of a moist fibrous material, such as bark or sawdust, or for pressing liquid out of cellulose pulp after the digestion or bleaching thereof. The material is fed up through a vertical shaft having screen walls and divided by a central partition into two halves. Said partition is moveable sidewise in order to press the material contained in one half of the shaft at a time towards the screen wall thereof. The press beam may also be formed with screen surfaces and cavities behind the same for letting out liquid. The press beam is pivoted at its lower end and rocked at its upper end. The liquid pressed ofl runs by gravity in the direction opposite to the direction of feed of the material. Successive batches of material are fed alternately to one and the other half of the shaft by a flap located at the lower end of the press beam and swinging through an angle of approximately 180 degrees.

This application is a continuation of application Ser. No. 652,265 filed July 10-, 1967, now abandoned.

The present invention relates to a press for dewatering of fibrous materials such as bark, sawdust, fibrous suspensions or similar. An object of the invention is to prevent dewatered material from being rewetted by the water pressed off. This is attained in principle by conveying the fibrous material through the press in the upward direction, the water on account of the force of gravity seeking to move counter-currently to the fibrous material, i.e. in the direction towards increasingly wetter material. Another object is to obtain an increased output capacity of a press having a swinging press body. Said object is reached by making the press body active on opposite sides, the material being advanced on one side thereof while the other side of said press body performs its pressing stroke, and vice versa when the press body swings in the opposite direction.

Other features of the invention whereby these and other objects are realized, are set forth in the appended claims.

A preferred embodiment of the press according to the invention will be more closely described herein below with reference to the accompanying drawing, in which FIG. 1 is an elevational view of the press, partly shown in cross-section along a vertical center plane, and FIG. 2 is a vertical sectional view taken at right angles thereto.

The shown press comprises a supporting structure or casing consisting essentially of four vertical exterior walls 11, 15, 13, 17 at right angles to each other. From the inner sides of said walls there project upwardly inclined flanges, e.g. 19, 21, which support four interior walls, 23, 27, and 29. Said walls are fixed, planar and essentially vertical and from the side faces of a vertical passage or shaft of a rectangular cross-section through which the material to be dewatered is fed in the vertical direction upwardly. Said material may consist of. bark obtained by debarking of wood, particularly in a mechanical way in cellulose pulp mills, and should be made burnable by being dewatered in the press to a dry content of approximately 50%. However, the press can also be used or adapted for dewatering of sawdust or other fibruos material, e.g. digested and/or defibrated cellulose pulp of a high consistency.

The two opposite walls 23, 27 towards which the central press body 31 is moveable in a manner to be described below, are perforated and form screen plates through which water is pressed out during the operation of the machine. The supporting flanges 19 are formed with through holes 33 enabling said water to flow through a space formed between the inner and outer walls and to depart through an outlet 35 at the bottom 37 of the casing. The remaining two inner walls 25, 29 which are parallel to opposite sides of the press body and along which the latter moves with a constant small gap, are preferably but not necessarily perforated and formed as screen plates. Water penetrating therethrough will find its way through the space behind the screen plates and through holes in the supporting flanges 21 to the outlet 35.

The plane screen plates 23, 27 merge at their lower parts in a semi-cylindrical'ly bent screen bottom 39 closing the shaft from below. The fibrous material to be dewatered is supplied immediately above said screen bottom through an inlet opening 41 located in the lower part of the wall 25 and receiving the material through a horizontal feed conduit 43. At its upper end the shaft has an upwardly directed outlet 45 from which the dewatered fibrous material is carried off by a motor-driven horizontal conveyor screw 47.

A horizontal axle 49 is journallcd in the low part of the casing and extends through the outer walls 13, 17, to which it is sealed by stufling boxes. Said axle extends across the lower part of the shaft in a position midway between the screen walls 23, 27 and concentric to the screen bottom 39. The lower end of the press body 31 is pivoted upon a widened eccentric part 51 of said axle 49. The press body can be swung about said axle by means of an operating device comprising a hydraulic or pneumatic cylinder 53, the piston of which is connected by means of a U-shaped yoke 55 and bearings 57 to the ends of a rod 59 extending through the upper end of the press body. By means of said operating device the press body can be moved from its central vertical position in the shaft in either direction so as to exert a pressure upon one or the other of the two flows of fibrous material advanced upwardly on opposite sides of the press body. The press body is designed generally as a plate or a beam dividing the axle 49 into two halves and the opposite edges of which move closely to the screen walls 25, 29. As shown in the drawing, said screen walls are substantially perpendicular to the axle 49 but may form a small angle to each other so that the shaft widens upwardly, the press body then also being somewhat wider at its upper part. The sides of the press body facing the screen walls 23 and 27 of the shaft, are perforated to form screen plates 61, 63. Said screen plates are essentially parallel to each other and are supported by flanges 65. Water penetrating through said screen plates runs through holes 67 in the flanges and cavities of the press body and departs from the lower end of the press body where the fibrous material has not yet been pressed and consequently its wetting by said water can be tolerated.

Keyed to the axle 49 on the opposite side of the eccentric 51 are sleeves 69, to which a pivotable flap 71 in a shape of a rectangular plate is attached. Said plate almost completely fills up the space in which it is moveable, i.e. its edges move closely up to or at a small distance from the walls 25, 29 and the screen bottom 39. The fibrous material fed through the inlet 41 is diverted by said flap alternately to one or the other side of the press body. By means of a motor 73 the axle 49 is periodically turned half a revolution in one direction and then half a revolution in the opposite direction, the flap 71 being swung from its shown essentially horizontal position into an opposite symmetrical position and then back again repeatedly. If desired, the flap may be perforated in order to let through such water as is given off by the fibrous material when pressed in one of the divisions of the shaft.

On account of the press body being journalled on the eccentric 51 carried by the periodically turned axle 49, the lower end of the press body will be displaced sideways during the operation. Thus, when the press body has been swung into its extreme right position shown in FIG. 1, the eccentric has its top situated on the right hand side, so that the upper as well as the lower parts of the screen plate 63 take their minimum distance from the fixed screen wall 27 and exert a heavy pressing action along the entire height extension of the right-hand shaft division. At the same time the left-hand shaft division is of maximum width at its upper as well as at its lower parts whereby the grip holding the more or less dewatered fibrous plug therein has been released and the stepwise movement thereof in the upward direction has been facilitated when the upward stroke of the flap 71 added a new batch of moist fibrous material to the bottom of said plug.

Of course, the movements of the press body and the flap should be coordinated so that they take place with the same frequency and at properly chosen time moments and velocities. However, the embodiment shown may be modified so that the movement of the eccentric is made independent of the movement of the flap, in which case the final pressing action caused by means of the eccentric at the lower part of the shaft may take place during the interval when the flap still remains in its extreme position and supports the fibrous plug from below.

Other modifications of the above described embodiment, which merely forms an example, are also possible within the scope of the following claims.

What is claimed is:

1. Press for dewatering of fibrous material such as bark, sawdust, fibrous suspensions or similar, comprising an essentially vertical shaft or passage having a screen wall, an inlet for fibrous material at its lower end and an outlet therefor at its upper end and provided with means for advancing fibrous material stepwise up through said shaft, a press body longitudinal in the direction of the shaft and moveable to and fro said screen wall by being pivoted about a horizontal axle extending through the lower part of the shaft, and an operating means for moving the press body to and fro the screen wall in order to press water out of the fibrous material and through the screen wall.

2. Press according to claim 1, characterized in that Cir 4- the shaft is provided with two opposite essentially vertical screen walls and that the press body is located between the same in order to cooperate alternately with one or the other of them.

3. Press according to claim 2, characterized in that the means for stepwise feeding the fibrous material up through the shaft comprise a pivoted flap attached to the horizontal axle, for introducing fibrous material alternately on one and the other side of the lower end of the press body.

4. Press according to claim 3, characterized in that the pivoted flap is adapted in either end position to form a bottom closure of the shaft division on one or the other side of the press body.

5. Press according to claim 1 characterized in that the operating means is connected to the upper end of the press body and arranged to swing the same in opposite directions from a vertical centre position and that the lower end of the press body is pivoted upon an eccentric attached to the axle, the turning of which displaces the press body to and fro the screen wall.

6. Press according to claim 1 characterized in that the press body is provided with a screen plate and cavities behind the same for carrying off water penetrating said screen plate.

7. Press according to claim 6, characterized in that substantially parallel screen plates are provided on opposite sides of the press body in order to cooperate with opposite screen walls of the shaft.

8. Press according to claim 1, characterized in that the shaft is rectangular in cross-section over the greater part of its height and is defined by two pairs of 0pposite, fixed, planar and essentially vertical walls of which at least some or preferably all are screen walls.

9. Press according to claim 8, characterized in that the lower end of the shaft is closed by a semi-cylindrical screen bottom concentric to the axle and that the fibrous material inlet is directed parallelly to the axle and opens out in a shaft wall perpendicular to the axle.

References Cited UNITED STATES PATENTS 525,803 9/1814 White. 942,135 12/1909 Davis.

1,837,034 12/1931 Freund 100209 XR 3,134,321 5/1964 Loehnert l00209 XR FOREIGN PATENTS 885,461 5/1943 France.

BILLY J. WILHITE, Primary Examiner US. Cl. X.R. 100l27, 209, 233 

